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Re: Using Li-ion cells in LED flashlights safely

Originally Posted by xzel87

Depends whether you are storing the light without the intention to use it during the storage period or storing as an emergency light. If you don't intend to use it, discharge the batteries till 3.7V then store in a cool dry place. Some say place it in an airtight ziploc bag and put in the fridge (some say freezer) but personally I wouldn't do this since you need to let the batteries come back to room temp before charging it.

Re: Using Li-ion cells in LED flashlights safely

Originally Posted by ganz-lite

It'll be an emergency light.

Then I strongly suggest you go with Lithium Primary batteries i.e. CR123 or Energizer L91s (AA). Put it in and forget about it. Li-Ion Rechargeables can keep their charge for quite a bit, but they will still self discharge, especially more so in extreme weather conditions (hot i.e. car glove box, car parked under baking sun).

EDIT: Forgot that you were referring to your 2x18650 light. Will that be the emergency light you were referring to?

Ideally, for cell longevity, Li-Ion Rechargeable cells are best stored at around 3.7V, however, this is not feasible since you are using it as an emergency light. My advice?, just keep it fully charged inside your light. If the light is kept in a nice cool place (drawer in the house) it should be fine. Capacity loss due to storing batteries fully charged, for us laymen, should not be noticeable at all. Test the light every so often and complete discharge and recharge every 3 months should suffice.

Re: Using Li-ion cells in LED flashlights safely

Originally Posted by xzel87

Then I strongly suggest you go with Lithium Primary batteries i.e. CR123 or Energizer L91s (AA). Put it in and forget about it. Li-Ion Rechargeables can keep their charge for quite a bit, but they will still self discharge, especially more so in extreme weather conditions (hot i.e. car glove box, car parked under baking sun).

EDIT: Forgot that you were referring to your 2x18650 light. Will that be the emergency light you were referring to?

Ideally, for cell longevity, Li-Ion Rechargeable cells are best stored at around 3.7V, however, this is not feasible since you are using it as an emergency light. My advice?, just keep it fully charged inside your light. If the light is kept in a nice cool place (drawer in the house) it should be fine. Capacity loss due to storing batteries fully charged, for us laymen, should not be noticeable at all. Test the light every so often and complete discharge and recharge every 3 months should suffice.

It'll be 2x32650, I'm looking at a jayrob light.

So if i keep it quiet, and if i keep it happy in a cool place (drawer or closet), it'll be happy so long as i discharge it every quarter (ie: walk the dog at night).

Re: Using Li-ion cells in LED flashlights safely

This is a very informative post. As a complete noob on batteries, I was going to ask you guys/gals which rechargeable batteries and charger would be a good fit for my situation. I feel kind of hesitant on ordering some now after reading this. Thanks for the warning.

Re: Using Li-ion cells in LED flashlights safely

I run an unprotected AW 16340 in my HDS. This is ok because the light itself is protected against over discharging the battery.

I have an Olight S1 baton, which does not have the same protection in the light as the HDS. I should still be ok running a quality unprotected cell in it because, probable worse case scenario is that I would over discharge the cell and negatively affect its capacity or life span. If I'm semi cautious with charging the cell in accordance with my use, it shouldn't be an issue.

What about running two unprotected 18500s or 18650s in an MD3 or MD4 body? I know Malkoff suggests protected cells, but I've seen where some people run the AW reds in series. Is this another (probable) worse case scenario of harming the cells, or am I looking at potential damage or injury to myself or the light?

I do not check the voltages of my cells, but charge them after significant use in a Nitecore I2.

Re: Using Li-ion cells in LED flashlights safely

Originally Posted by JBorneu

Ahoy there

I created this guide because I felt we lacked one single comprehensive guide which tells newbies how to use Li-ion cells in a safe manner in their LED flashlights. Now I know why: At least the "comprehensive" part is impossible.

Using Li-ion cells in LED flashlights safely for newbies

5 Chargers....

Hi
Can you please add some info on the solar powered string lights which have batteries like 3.7v, 14500, 400 mah ICR?
Want to know if it matters which company or quality one buys for a low usage lights like these?
So links to best buys may help if you know
Thank you for the explanation-looks comprehensive and good

Re: Using Li-ion cells in LED flashlights safely

Originally Posted by Dr. Manhattan

You should mention something about storage. Please clarify if the batteries are ticking bombs which will explode when the discharge under 3V...

No that wont happen, worse case is when they are charged from a low voltage. Most cells these days have a minimum low of 2.5v(some 2.8v). Its not recommended to go bellow this voltage. If you do, charging asap is key and not to leave for long periods..............this over time causes a build up due to the chemistry inside and can go south when charged.

Store around 3.6v in a cool dry place if for long periods. If in a flashlight, lock out to eliminate any parasitic drain and check periodically . Even if it means running the light for 5m and topping back off or leaving around 4.1v which can help the life over time(years).

When a cell is shorted, this causes a risk and with the pressure inside(pipe bomb), so not only are voltage checks important over time, but also checking over the cell, making sure the wrap/s are not torn/damaged.................if so, remove and replace with readily available wrappers (cheap as chips). Many youtube vids to show how easy to fit..........I slip one on the cell, check length which usually is a few mm too long, remove and cut off with scissors. Re fit on the cell, heat with hair dryer(carefully) to shrink wrap on cell.............check all is well and good to go again.

Not into great detail, just keeping it simple like me but those are some basics.

Too add, there are usually lots of warnings even if a flashlight will not flash or blink when close to 3v. Not being able to get into higher modes is a simple indication to charge back up. Ideally, try and not go bellow 3.3-3.5v to keep it within a nice margin of possible...........how will i know when its 3.5v???? Well if a new light, use for a set period, check voltage and repeat to get an idea. For example it may take 2hrs of use to get to 3.5v on medium and turbo uses. So if your uses is simply 30m a day, every 4 days top cell off(just a rough example).

Re: Using Li-ion cells in LED flashlights safely

@ven Thanks it now feel a little better. Its my first Li-ion battery LED flashlight and I still got the feeling that I have bought a pipe bomb :-) I have bought a Xtar Ant-MC1 Plus charger and a Keeppower 3500 mah protected battery which should be good quality. The flashlight is a Astrolux S1 which should have necesarry safety mechanisms for example low voltage protection.

Re: Using Li-ion cells in LED flashlights safely

First of all it is important to understand that Li-ion batteries which you have in every cell phone are an excellent type of battery BUT…they are known to explode or self ignite, as just recently happened with some of the Galaxy Note 7 phones.

Protected Li-ion batteries are batteries which have a circuit board on them which prevents the battery from being reversed charged or reverse operated. Now if you have a charger that is also reverse polarity protected than even if you have a non protected battery it will not be damaged if placed the wrong way in the charger.

Unfortunately there are many low grade batteries and substandard charges sold on the market or supplied with flashlights, so you have to be very careful about the battery that you use and the charger you are using.

Remember there are many products manufactured in China (like iPhone) the difference is where it is made and the specification according to which it was produced.

Our recommendation is to only buy quality protected batteries making sure that the rated capacity (mAh) is the real capacity (In many cases the rated capacity is much higher than the actual capacity). It can be easily verified when testing the battery as per the below picture.

Also make sure you have a quality charger that is UL certified (confirming to the US Safety Standards) there are many dangerous cheap chargers, do yourself a favor and avoid them. Check for the UL marking on your charger. Verify the charging current is at least 1000mA unless you want to wait for hours until your battery is charged! (See below picture)

Re: Using Li-ion cells in LED flashlights safely

Looking to find out what a safe resting voltage for a Olight 550mA IMR cell (came with my S1R Baton) is. I have seen several posts that say never let it go below 3.6V resting, but they are all very old. Not sure with the newer batteries that is still true. The light has an indicator that shows when 10-15% capacity is remaining, but not sure if I should rely on that or check the voltage periodically.

Tried finding a chart with resting V vs capacity remaining but no luck.

Re: Using Li-ion cells in LED flashlights safely

See the charts at the bottom. Those are somewhat older cells, but hopefully things are still fairly close.

That article was super helpful. I have seen it before, but I did not really understand the measurement technique until I re-read it again this time. But while being super helpful, it does not answer my specific question. I will start a new thread, as I don't think this is the right place to further this discussion.

Re: Using Li-ion cells in LED flashlights safely

Originally Posted by sbslider

Looking to find out what a safe resting voltage for a Olight 550mA IMR cell (came with my S1R Baton) is. I have seen several posts that say never let it go below 3.6V resting, but they are all very old. Not sure with the newer batteries that is still true. The light has an indicator that shows when 10-15% capacity is remaining, but not sure if I should rely on that or check the voltage periodically.

Tried finding a chart with resting V vs capacity remaining but no luck.

First you need to clarify what you mean by "safe resting voltage" and what purpose you will use if for. There are a few possible interpretations.

Maybe you are asking if you can determine if a certain resting voltage implies that the cell was never drained too low in its prior use. That's not always possible to determine, but one could make some guesstimates if you know the (peak) current of the device, the IR of the cell etc.

Or maybe you mean to ask if it is safe to store the cell at that voltage for long periods? Please clarify.

Re: Using Li-ion cells in LED flashlights safely

Originally Posted by Gauss163

First you need to clarify what you mean by "safe resting voltage" and what purpose you will use if for.

I will say that my OP was not very clear for what my intent was. I have a Olight S1R, the the included ORB-163C05 IMR RCR123A. My goal is to be able to pick up the light after it has been off for a time, measure the voltage the tail, and decide if I should use it or charge it. In looking into the battery voltage range vs capacity question, I saw several comments that warned to not use a rechargable Li-ion battery that measured less than 3.6V, that it was dangerous. I got a bit caught up in the safety aspect of how low the voltage could go before recharging. Not to dismiss safety, but I am not worried about that in this particular case any more. That's why I started a new thread.

Re: Using Li-ion cells in LED flashlights safely

3.6v sbslider is not too low, that is the nominal voltage , also a good storage voltage(maybe 40-50% capacity. Most cells (variable) have a min voltage of 2.5-2.8v, so to play it a little safer, 3v minimum is a safe voltage to not go bellow(leaves a little room). But even then, if the voltage is bellow the min spec, for example it is 2.3v measured. As long as the cell has not been in this state for a period of time, it should charge up fine(being monitored to add) with minimal issue/potential damage. Most lights do have a built in LVP, also even without the LVP(low voltage protection) not many flashlights will power up at 3v, or certainly not in high modes. As with the load and voltage sag, it will blink or go out letting you know.

The little RCR123a cells(16340) do not have much capacity, usually 6-700mah in the tank(yours is 550mah ). Its a good idea to use the light and check cell voltage after a few uses. This way you will get an idea of how much use and where the voltage will roughly be. With my 16340 cells, i tend to top off back to 4.2v after use, as even a little use with higher levels(exl low and moon modes) does eat through the mah pretty quick. So by topping them back up to 4.2v, i know exactly where i am up to and good to go again. Now at 3.6v, you dont have that much left, certainly if your going to be attempting higher levels(if the light allow use at that V). If its for regular use, i would certainly carry a spare cell or 2 for the light. If you find your swapping cells out regular, then a compact 18650 light may work better for you. I love 16340 lights, the form for me is perfect for EDC uses, but not ideal for any decent duration. I would struggle in work for example, where a few hours of 200lm( ish as a variable) might be needed.

3.6v is a good place to top back up yes, but there are no safety issues at that voltage, nor going lower towards 3v. Maybe he was just giving you a large buffer to be extra safe, but i am sure the olight mentioned will not work bellow 3v.

Re: Using Li-ion cells in LED flashlights safely

Originally Posted by Benson

One other useful size you might want to mention was the 17500s; they're 1.5 CR123 cells, so you can stack 2 of them in a 3xCR123 light.

And that's where the 17500s shine -- 2 17500s at 4.2V starts at 8.4V, whereas 3 primaries @ 3V each start with 9V. Since the Li-ion hold up better under load, they work out great in most such applications.

I admit to being a n00b and know this is an old thread...

I’m not understanding how 2 17500s at 4.2V/each is better and “holds up better under load” than 3 CR123As at 3.0V/each. Would someone explain this to me?